The Synaxarion of Saint John the Faster reveals to us why he became
known by that epithet.
"His abstinence was like this: he ate nothing for
six days, and on the seventh day he ate a little fruit: either a melon,
or grapes, or figs. That's how he fed himself for the entire time of
his patriarchate."
Saint John the Faster was Patriarch from April 11,
582 to September 2, 595, which means this was how he fasted for more
than 13 years.
The Canons of Saint John the Faster reflect the great regard he held towards fasting in healing a Christian from the passions of the flesh and secret sins, together with prostrations and almsgiving, though the strict way he applied such things to himself shows how lenient he was with others.